class Gem::Request

def self.verify_certificate_message(error_number, cert)
  return unless cert
  case error_number
  when OpenSSL::X509::V_ERR_CERT_HAS_EXPIRED then
    require "time"
    "Certificate #{cert.subject} expired at #{cert.not_after.iso8601}"
  when OpenSSL::X509::V_ERR_CERT_NOT_YET_VALID then
    require "time"
    "Certificate #{cert.subject} not valid until #{cert.not_before.iso8601}"
  when OpenSSL::X509::V_ERR_CERT_REJECTED then
    "Certificate #{cert.subject} is rejected"
  when OpenSSL::X509::V_ERR_CERT_UNTRUSTED then
    "Certificate #{cert.subject} is not trusted"
  when OpenSSL::X509::V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT then
    "Certificate #{cert.issuer} is not trusted"
  when OpenSSL::X509::V_ERR_INVALID_CA then
    "Certificate #{cert.subject} is an invalid CA certificate"
  when OpenSSL::X509::V_ERR_INVALID_PURPOSE then
    "Certificate #{cert.subject} has an invalid purpose"
  when OpenSSL::X509::V_ERR_SELF_SIGNED_CERT_IN_CHAIN then
    "Root certificate is not trusted (#{cert.subject})"
  when OpenSSL::X509::V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY then
    "You must add #{cert.issuer} to your local trusted store"
  when
    OpenSSL::X509::V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE then
    "Cannot verify certificate issued by #{cert.issuer}"
  end
end